Fix: encoding, path to NZBfile on Windows, code formatting, round the…

… max failed limit (#5)

- fixed a UnicodeEncodeError exception that occurs when using special characters in names;
- fixed several "NoneType" errors;
- fixed wrong path to NZB file on Windows;
- rounded the failed limit precision value;
- added tests and pipeline for tests;
- formatted the code using Black.

.github/workflows/tests.yml

@@ -0,0 +1,19 @@
+name: tests
+
+on:
+  push:
+    branches:
+    - feature/*
+    - master
+  pull_request:
+    branches:
+    - main
+
+jobs:
+  tests:
+    uses: nzbgetcom/nzbget-extensions/.github/workflows/python-tests.yml@main
+    with:
+      python-versions: "3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12"
+      supported-python-versions: "3.8 3.9 3.10 3.11 3.12"
+      test-script: tests.py
+      debug: true

.gitignore

@@ -0,0 +1 @@
+__pycache__

README.md

@@ -3,13 +3,12 @@ If you need support for Python 2.x versions then you can get legacy version v1.1
 
 ## NZBGet Versions
 
-- pre-release v23+ [v3.0](https://github.com/nzbgetcom/Extension-Completion/releases/tag/v3.0)
-- stable  v22 [v2.0](https://github.com/nzbgetcom/Extension-Completion/releases/tag/v2.0)
-- legacy  v21 [v2.0](https://github.com/nzbgetcom/Extension-Completion/releases/tag/v2.0)
+- stable v23+ [v3.0](https://github.com/nzbgetcom/Extension-Completion/releases/tag/v3.0)
+- legacy v22 [v2.0](https://github.com/nzbgetcom/Extension-Completion/releases/tag/v2.0)
 
 # Completion
 
-[NZBGet](https://nzbget.com) [script](https://nzbget.com/documentation/post-processing-scripts/) that checks if the data in the NZB file is sufficiently complete at your usenet provider(s), before starting the download. If incomplete it would wait for a certain period and check the completion of the NZB file again. This check is done by requesting the header status, and is in normal cases done within seconds (like 1 - 5 sec. for a 1 GB file). This method is significantly faster than when NZBGet would report a failure, after actual downloading a (part of) the files that end up incomplete. The script is typically useful for issues related to:
+[NZBGet](https://nzbget.com) [extension](https://github.com/nzbgetcom/nzbget/blob/main/docs/extensions/EXTENSIONS.md) that checks if the data in the NZB file is sufficiently complete at your usenet provider(s), before starting the download. If incomplete it would wait for a certain period and check the completion of the NZB file again. This check is done by requesting the header status, and is in normal cases done within seconds (like 1 - 5 sec. for a 1 GB file). This method is significantly faster than when NZBGet would report a failure, after actual downloading a (part of) the files that end up incomplete. The script is typically useful for issues related to:
 - very recent posts,
 - failed downloads, which after a while are just ok (propagation issues),
 - incomplete posts,